LEEPA CONSTRUCTION

(1)

Leepa

Guidelines for the compliant construction of

Leepa-type timber post and beam houses

(2)

Plinth

The plinth should be stable and well

packed.

The base plate and frame should be

kept dry.

The plinth may be raised

The plinth may be raised above groundabove ground

level, for protection from snow. In this

case the ground oor should be maxi

case the ground oor should be maxi-

-mum 8 ft high.

mum 8 ft high.

The plinth or back wall may be

con-structed as retaining walls, but should

structed as retaining walls, but should

not retain a height greater than 8 ft.

Back wall

A rear wall may be constructed of

good quality stone masonry with

through and corner stones.

The wall should be min 24 inches at

top and wider at

top and wider at base, the wall may bebase, the wall may be

stepped or sloped on rear side.

The posts supporting the upper oor

must be separate and inside the wall.

Plinth and back wall

Leepa

Timber posts inside and separate to the wall. RCC bands between well laid dry stone masonry.

RCC bands can strengthen the wall.

Upper storey frame is xed to top of the wall.

A good plinth protects the base plate and ensures it dries quickly.

Traditional practice is to have back wall of stone.

(3)

Conguration

/

/ Plan

Plan

The building should be symmetrical and

balanced.

The best plan shape is square.

The traditional layout of 3 equal bays

wide x 3 equal bays long is recom

wide x 3 equal bays long is recom-

-mended.

mended.

The external walls should be balanced

in weight, with all sides equal.

The building length should not be

greater than 3 times its width.

Core and stiffness

There should be full height walls

pro-vided in both plan directions.

vided in both plan directions.

Load bearing walls should be placed

over each other.

Conguration

Section

The building should

The building should be heavier in lowerbe heavier in lower

storeys and lighter in upper

storeys and lighter in upper storeys.storeys.

Max storey height 10

Max storey height 10 ft. Storft. Storey heightsey heights

should be equal.

Stone basement storey height max 8

ft.

ft. Stone masonry walls Stone masonry walls should followshould follow

Bhatar construction principles.

The total building height should not be

greater than the plan length.

More than 1 storey retaining wall. Plan area not same

(4)

Horizontal

Each storey should be a box with its

own top and bottom plates and posts.

The building is a series of separate

boxes stacked on top of each other.

Base plate should be provided under all

posts and wall plates above all posts.

Base and wall pates minimum size 6 x 5

inches.

Plates should be long continuous good

quality seasoned

quality seasoned timbertimber..

Floor joists should be spaced at maxi

Floor joists should be spaced at maxi-

-mum 2 ft cc

mum 2 ft cc and may be overlappedand may be overlapped

over the oor beam.

These timber sizes are good for double

storey construction.

Vertical

Posts should provided at maximum 6 ft

spacing.

Posts min section size: 6 x 5 inches

Posts should be made of a single piece.

Where there are larger clear spans

the posts should be larger section or

closer spaced.

All timber sizes recommended are

good for double storey construction

Timber Frame Sizes

Leepa

(5)

Walls

External walls may be constructed

of load bearing timber

of load bearing timber planks, tplanks, timberimber

boarding or dhajji inll.

The maximum unrestrained wall length

is 15 ft.

The building should be divided into

small regular rooms.

The walls should be constructed of

dhajji inll in lower storeys and s

dhajji inll in lower storeys and solidolid

timber planks in upper storeys.

Floors

Floors and ceilings add stiffness to the

frame.

It is recommended to use solid oor

boards minimum 3/4 inch thick.

Corners and Openings

Openings should not be greater than

25% of the overall wall area.

Plan length of the wall between the

corner and nearest opening should not

be less than 5 ft.

Plan length between any other two

openings should not be less than 2.5 ft.

Openings should not be larger than 5 ft

wide.

Openings should distributed equally in

the plan.

Openings should be fully framed.

Frames greater than 2 ft wide should

have sub frames.

Walls and openings

Verandahs

V

Verandah frames erandah frames may be constructedmay be constructed

of smaller

of smaller timber sections. timber sections. The framesThe frames

may be stiffened with balustrades or

other inlled sections

Knee braces can also be used from the

post to the wall plate.

Distance from the corner to opening must be minimum 5 ft.

L

(6)

Vertical

Posts should be xed to base plates

and wall plates with mortice and tenon

joints.

Joints should also be nailed.

In new construction the timber sizes

have been reduced making it more

dif-cult to make a correct joint.

cult to make a correct joint.

Timber section sizes should be

mini-mum 5 x 6 inches in the main frame.

mum 5 x 6 inches in the main frame.

T

Tenon size enon size and location should and location should bebe

correct to avoid breaking off.

Horizontal

Base and wall plates should be

con-nected at the perpendicular joint with

nected at the perpendicular joint with

an overlap cross halved joint.

Bases and wall plates should be spliced

with a scarf joint or Kashmiri joint.

These joints should be pegged.

In new construction the horizontal

joints are butt or lap

joints are butt or lap jointed, jointed, thesethese

need to be

need to be improved.improved.

The timber section used in the base

plate should be best quality seasoned

heartwood.

heartwood. It carries the load It carries the load of theof the

building and is most exposed to

weathering.

Joints and Framing

Leepa

(7)

Timber Boarding

Use timber planks

Use timber planks of approof approximately ximately 11

1/2

1/2 inches thick to inches thick to make tmake timber loadimber load

bearing walls, or as cladding to a

bearing walls, or as cladding to a timbertimber

frame.

The boards should be

The boards should be interlocked atinterlocked at

the corners to provide excellent earth

the corners to provide excellent earth-

-quake resistance.

quake resistance.

The boards should be xed to each

other by pegging to

other by pegging to the board abovethe board above

and below.

The xing method and board thickness

ensures the boards do not warp or

weather..

At intermediate posts, boards should

be inserted in grooves for better xing.

Boards should not be cut off without

proper interlocking. This is a

proper interlocking. This is a weakerweaker

detail.

Boards should not be nailed close to

the end grain weakening the planks at

the corners.

Boards overlapped but not

Boards overlapped but not interlockedinterlocked

at the corners are not sufcient.

Thinner boards and poor xing by face

nailing means increased warping and

weathering.

Boarding should not be used as only

short wall lengths.

Joints and Boarding

Boa

(8)

Dhajji

Previous construction used well

Previous construction used well packedpacked

dhajji inll masonry of minimum 6 inch

usually 8-10 inch thickness.

Flat boards were used between the

main posts to hold the inll and brace

the frame.

The inll performed well in the earth

The inll performed well in the earth-

-quake,

quake, with minor loosening or with minor loosening or fallingfalling

out of inll

out of inll stones. stones. The mortar The mortar shouldshould

be weak.

The earthquake energy is shed by the

Dhajji.

Dhajji. This protects This protects the main the main timbertimber

frame.

New Inll

In new construction, in situ

In new construction, in situ concrete,concrete,

stone masonry with

stone masonry with sand cement mor-sand cement

mor-tar and concrete blocks are being used.

tar and concrete blocks are being used.

All of these are too stiff and will not

perform as well as weaker Dhajji inll.

They may fall out as entire panels or

break the timber frame.

They also provide no timber bracing

for the timber frame.

Stone masonry laid dry or with weak

mortar may not be used without Dhajji

bracing in upper oors.

Sand cement mortar is not good for

timber

timber durabilitydurability..

Dhajji and Inll

Leepa

Stonework with no bracing.

Masonry with sand cement mortar.

In situ concrete inll.

Even small areas of in situ may weaken the frame.

(9)

Platform Frame

Each storey should be constructed as a

box with its own bas

box with its own base plate, posts ande plate, posts and

wall plate.

wall plate. This is This is a platform frame.a platform frame.

In new construction some houses do

not have continuous plates, and posts

are bearing on the wall plate of the

sto-rey below.

rey below.

The plates are necessary to act as

continuous bands and to allow each

storey to act independently.

RCC frame members

RCC beams and columns should not

be used in combination with timber

framing.

They do not

They do not have proper connectionshave proper connections

with the timber and

with the timber and they will not per-they will not

per-form well in ear

form well in earthquakes, thquakes, as they are as they are aa

different weight, and unrestrained.

Insulation

Use of heavy mud or concrete in

Use of heavy mud or concrete in thethe

oors or roof for insulation should be

discouraged.

discouraged. It adds to the It adds to the load of theload of the

building.

building. The roof The roof should be should be light.light.

Lightweight insulation options should

be developed.

Mixed Construction

Base plate not continuous, posts xed on wall plate below.

RCC column xed to

RCC column xed to timber beam. Ttimber beam. This is not his is not permitted.permitted.

RCC

(10)

LEEPA CONSTRUCTION

Leepa

Leepa

Guidelines for the compliant construction of

Guidelines for the compliant construction of

Leepa-type timber post and beam houses

Plinth

Plinth

Back wall

Back wall

Plinth and back wall

Plinth and back wall

Leepa

Leepa

Conguration

Conguration

/

/ Plan

Plan

Core and stiffness

Core and stiffness

Conguration

Conguration

Section

Section

Horizontal

Horizontal

Vertical

Vertical

Timber Frame Sizes

Timber Frame Sizes

Leepa

Walls

Walls

Floors

Floors

Corners and Openings

Corners and Openings

Walls and openings

Walls and openings

Verandahs

Verandahs

Vertical

Vertical

Horizontal

Horizontal

Joints and Framing

Joints and Framing

Leepa

Timber Boarding

Timber Boarding

Joints and Boarding

Joints and Boarding

Dhajji

Dhajji

New Inll

New Inll

Dhajji and Inll

Dhajji and Inll

Leepa

Leepa

Platform Frame

Platform Frame

RCC frame members

RCC frame members

Insulation

Insulation

Mixed Construction

Mixed Construction

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